does a LSD reduce torque steer in a FWD car?

[Pixelpeep]

There was a discussion a while back about someone buying a pre LSD FN2 Civic type-R and i, (hopefully not alone) was under the impression a limited slip differential would reduce torque steer?

Someone then said that this is not the case at all and can actually cause quite the opposite effect.

This makes me quite sad as i own a 2009 Astra VXR and it torque steers like a b*tch!

Can anyone explain what the case is and give a little technical background please?

[Zoobeef]

Pixelpeep said:

There was a discussion a while back about someone buying a pre LSD FN2 Civic type-R and i, (hopefully not alone) was under the impression a limited slip differential would reduce torque steer?

Someone then said that this is not the case at all and can actually cause quite the opposite effect.

This makes me quite sad as i own a 2009 Astra VXR and it torque steers like a b*tch!

Can anyone explain what the case is and give a little technical background please?

Can you not just hold the steering wheel tighter?

[balls-out]

An LSD will allow different torques to be developed by each wheel - an open diff does not.
This is likely to increase "pull" on the steering ie torque steer

[rhinochopig]

Pixelpeep said:

There was a discussion a while back about someone buying a pre LSD FN2 Civic type-R and i, (hopefully not alone) was under the impression a limited slip differential would reduce torque steer?

Someone then said that this is not the case at all and can actually cause quite the opposite effect.

This makes me quite sad as i own a 2009 Astra VXR and it torque steers like a b*tch!

Can anyone explain what the case is and give a little technical background please?

There are LSDs and there are LSDs. They all work differently and they all affect the way the car drives in different ways.

[sjabrown]

Depends on many variables- geometry, tyres , LSD. Torque biasing diffs aren't that noticeable but an aggressive plated diff can really tug at the wheel especially without power steering to help

[littleredrooster]

30+ Years ago, I used to rally a Mini with a potent motor and an LSD. The torque-steer was savage - when dropping the clutch from a standstill, your reactions had to be mighty quick to catch and correct the torque steer before it turned randomly left or right into a hedge/ditch/marshal!

Trying to get the thing going in a straight line was the first challenge!

[CapriV6S]

Drove a Mk3 Escort RS Turbo S1 (the original 1985 white one with lsd) years ago, an original-appearance car but modded to around 190bhp.

Torque steer pulled it across the road on full boost. Dangerous unpredictable car to drive fast on a wet road if you weren't used to it.

However, modern diffs are designed to prevent this and to be more controllable, especially with much higher power outputs available these days I think.

I hope anyway!

[Scuffers]

toque-steer per say has nothing to do with what diff is installed (it;s to do with suspension kinematics and drive line setup), however, if a car is prone to toque-steer, then adding an LSD can only make it worse.

[NateWM]

Scuffers said:

toque-steer per say has nothing to do with what diff is installed.

Wrong.

Granted, it all depends on many variables, but the type of diff is almost key! I had a Civic a couple of years ago that was running a Turbo B16 at just shy of 400hp. At first it was fitted with the standard open diff. If you floored it in 2nd at 3,000rpm, the revs would build, the turbo would come alive and it would spin up one wheel. There was no drama (at most the steering wheel would give a little wiggle) and you would carry on wheelspinning down the road.

A few months later, I fitted a Cusco 2-way L.S.D. When doing the same thing (flooring it in 2nd etc.), it would still wheelspin but would instead pass the power between both front wheels, which meant you had to fight to keep the car in a straight line, not to mention how much easier it was to get the power down and how much better it went round corners. Was expensive, but so worth it!

[balls-out]

Scuffers said:

toque-steer per say has nothing to do with what diff is installed (it;s to do with suspension kinematics and drive line setup), however, if a car is prone to toque-steer, then adding an LSD can only make it worse.

On balance.... Right!

[Adam205]

Scuffers said:

toque-steer per say has nothing to do with what diff is installed (it;s to do with suspension kinematics and drive line setup), however, if a car is prone to toque-steer, then adding an LSD can only make it worse.

Torque steer is caused by an imbalance in force applied around the steering axis on each side. If there is no scrub radius then there can in theory be no torque steer. These new suspension systems that separate the king pin from the strut do so in order to achieve this.

However there are a variety of different things that can cause the force imbalance. A very major one is an aggressive LSD that allows a big torque diffence. Another smaller one is a difference in driveshaft angle, hence a lot of FWD cars will have one two-piece driveshaft.

[Scuffers]

Adam205 said:

Scuffers said:

toque-steer per say has nothing to do with what diff is installed (it;s to do with suspension kinematics and drive line setup), however, if a car is prone to toque-steer, then adding an LSD can only make it worse.

Torque steer is caused by an imbalance in force applied around the steering axis on each side. If there is no scrub radius then there can in theory be no torque steer. These new suspension systems that separate the king pin from the strut do so in order to achieve this.

However there are a variety of different things that can cause the force imbalance. A very major one is an aggressive LSD that allows a big torque diffence. Another smaller one is a difference in driveshaft angle, hence a lot of FWD cars will have one two-piece driveshaft.

which is pretty much exactly what I said.

if a given setup does not have torque steer to start with, then great, if not, adding a device that proportions toque asymmetrically is only going to make it worse.

[Daniel1]

CapriV6S said:

Drove a Mk3 Escort RS Turbo S1 (the original 1985 white one with lsd) years ago, an original-appearance car but modded to around 190bhp.

Torque steer pulled it across the road on full boost. Dangerous unpredictable car to drive fast on a wet road if you weren't used to it.

However, modern diffs are designed to prevent this and to be more controllable, especially with much higher power outputs available these days I think.

I hope anyway!

I had a S2 running about a million psi and that would give you a good fight. I had forearms like popeye before it rusted away!

[Adam205]

Scuffers said:

Adam205 said:

Scuffers said:

toque-steer per say has nothing to do with what diff is installed (it;s to do with suspension kinematics and drive line setup), however, if a car is prone to toque-steer, then adding an LSD can only make it worse.

Torque steer is caused by an imbalance in force applied around the steering axis on each side. If there is no scrub radius then there can in theory be no torque steer. These new suspension systems that separate the king pin from the strut do so in order to achieve this.

However there are a variety of different things that can cause the force imbalance. A very major one is an aggressive LSD that allows a big torque diffence. Another smaller one is a difference in driveshaft angle, hence a lot of FWD cars will have one two-piece driveshaft.

which is pretty much exactly what I said.

if a given setup does not have torque steer to start with, then great, if not, adding a device that proportions toque asymmetrically is only going to make it worse.

I wasn't disagreeing, just elaborating on 'it's to do with suspension kinematics and drive line setup'.

[HorneyMX5]

I had a classic mini with a fair bit of power a few years ago and that torque steered a bit. Drove a demo car from a tuning company with equal length driveshafts and that was incedible. Always wanted to get the kit for mine but never did before I sold it.

nick

[DanDC5]

Pixelpeep said:

There was a discussion a while back about someone buying a pre LSD FN2 Civic type-R and i, (hopefully not alone) was under the impression a limited slip differential would reduce torque steer?

Someone then said that this is not the case at all and can actually cause quite the opposite effect.

This makes me quite sad as i own a 2009 Astra VXR and it torque steers like a b*tch!

Can anyone explain what the case is and give a little technical background please?

I find this odd to be honest, I had a VXR before the Integra, 290bhp and just over 350lb/ft, it barely registered a movement on the steering wheel in any gear in sport mode and with the TC turned off. One of the biggest fallacies in magazines and on forums at the moment is the VXR is an undriveable torque steering monster. Yours may have a problem.

[BoostMonkey]

DanDC5 said:

I find this odd to be honest, I had a VXR before the Integra, 290bhp and just over 350lb/ft, it barely registered a movement on the steering wheel in any gear in sport mode and with the TC turned off. One of the biggest fallacies in magazines and on forums at the moment is the VXR is an undriveable torque steering monster. Yours may have a problem.

True, but there not a good handling car either and you have to balance the power so carefully coming out of corners that means a similar competitor like the Focus ST is 6/7m further round the apex.
An LSD on the VXR and a bumpy country road could see higher torque steer, but on a flat surface possibly less it all depends on the situation - and its not as clear cut as fit an LSD and the TS magically disappears

[DanDC5]

Not saying it is, mine wasn't running an LSD and I never had a problem. The Integra is a lot worse than the Astra at times on B-roads purely because the LSD snatches the car across the road, at times having the LSD makes it worse to be honest. But I certainly wouldn't say an ST running the same power is any better at dragging it's ass out of a tight corner after owning one and been in the other and experiencing it to know. Biggest difference on both cars and one I'd recommend highly to get them handling better is fitting Eibach springs. Night and day worth of difference in both.

[Krikkit]

What type of LSD does the DC2/DC5 teg run?

[s m]

Krikkit said:

What type of LSD does the DC2/DC5 teg run?

Torsen type